1. Field of the Invention
The present invention relates to devices, systems, and processes useful for controlling access to data and computer executable instructions contained on computer readable media, and more specifically to controlling such access in accordance with restrictions on the number of copies of such data and instructions that are permitted to be used.
2. Brief Description of the Related Art
Optical jukeboxes have been proposed in the past, as well as systems and methods for using a magnetic media drive (e.g., hard disk drive) to cache some or all of the contents of optical media housed in the jukebox. For example, U.S. Pat. Nos. 5,845,104, 6,260,143, and 6,502,175 describe exemplary systems and methods. While prior systems and methods may have been suitable for some uses, they suffer from some drawbacks and/or are not well suited for some applications.
One of the issues that can result from the use of optical jukeboxes with personal computers (PCs) is that many copyright holders are concerned about protecting their intellectual property, and specifically the copyrights to the contents of a CD or DVD. For example, if there is one copy of a game on a CD in the jukebox, but two people want to play that game at the same time, the hard drive cache used by the jukebox could easily have enough bandwidth to cache the CD, and two (or more) different machines enough data, for the games to operate properly on each of the PCs of the two users. This kind of multiple, simultaneous use of the single copy of the game may, however, run afoul of the copyrights of the copyright holder.
It has previously been proposed to use an optional subscription number limit to limit media use with a DVD/CD jukebox having a hard drive cache; one such system has been commercially available from TenXpert (Austin, Tex.). The TenXpert system, however, requires that media having the same user-license limit be grouped together in the same share volume, and then merely permits a limit to be set on the number of users permitted to simultaneously access that share volume. Thus, the TenXpert system merely counts the number of users accessing a specific portion of the media, and permits a user or administrator to impost a limit on the number of simultaneous users of that portion. Thus, this system relies heavily on these limits being properly set by a person.
PowerFile (Los Gatos, Calif.) has proposed a DVD Jukebox that caches the directories of the jukebox's media on a PC, but the number of accessible discs is limited to the number of optical drives in the jukebox. CD Anywhere (V Communications, Inc, San Jose, Calif.) is commercially available computer software that permits a user to copy the contents of one or more CD's onto a hard disk drive, but copy protection and licensing issues are left to the discretion of the user. These and other prior systems and methods do not address the problems associated with consumer copy protection and licensed use. Accordingly, a need remains for systems and methods that specifically accommodate the use of multiple copies of a single title in a jukebox, while providing a mechanism for restricting access to and/or use of the contents based on the number of copies of or licenses to any single title.